I got the same problem Ive try everything I can think of and nothing seems to be working it's just very stressful.
Is there a reason why you need to leave food down and can’t just feed at certain times? Also raised water bowls can help depending on what your dog is. Generally though you just need to stop child getting to them. My little one has discovered the water bowls recently and is loving splashing in them but if he gets close now we just move him away, give him something else to do. If he is being persistent about it we play in his pen for a bit till he forgets about them. He has never been allowed anywhere near the food bowls though, always kept out the way around feeding as that’s a risk I’m not willing to take.
My daughter did this as well. She would be constantly at their food and water bowls. Every time she went near them I would say no firmly and remove her from them and give her an appropriate activity. Same thing with if she tried to pet them while they were eating. A firm no, not when their eating, and removed her to another room. She just ignores their bowls now and them if they're near them. I just had to watch her like a hawk for a while so that I caught her everytime she tried to go near the bowls especially the water. Our bowls are in the hall, so if I was busy in the kitchen I took her in with me and started closing the door so she couldn't slip off to the bowls if I turned my back for a second lol. Lasted a few months then she got the message.
Persistence and solid boundaries. She does not touch the bowls and every time she goes to you need to pick her up and put her elsewhere. If you react to it at all she's just gonna laugh and do it more for the reaction. Consistency is key